In various pneumatic or vacuum systems, atmospheric systems, fluid handling systems and/or devices, broadly referred to as "fluid handling systems" herein, it is necessary to remove condensates, other fluids, (collectively referred to as "fluids" herein), and other foreign materials to insure proper operation. Various devices such as separators, filter traps, dryers, drip-legs, etc., are used for separating out and collecting fluids and other materials, and such devices are generally provided with drain valves for discharging the collected fluids from the pneumatic system or device. Typically, such devices include an air inlet, an air outlet and a mechanism for generating fluids such as a filtering element mounted between the inlet and outlet in the flow path or a process such as changing air and/or surface temperatures. Such devices also include an enclosed geometry such as a reservoir, length of pipe, or filter bowl through which the air flow is at least partially passed causing the moisture and other fluids in the air to be collected and condensed on the inside surface of the reservoir or bowl. The force of gravity causes such condensed materials to accumulate at the bottom of the reservoir together with any other foreign objects. Periodically, this accumulated material and liquid must be discharged when the reservoir or filter bowl has become full of material.
Numerous drain systems have been devised for the discharge of the accumulated material. Two such devices are shown in U.S. Pat. No. 3,980,457, issued to J. I. Smith on Sep. 14, 1974, and in U.S. Pat. No. 3,993,090, issued to Paul M. Hankison on Nov. 23, 1976. In the first of these two patents, there are a pair of valves, a pilot valve and a discharge valve. The pilot valve is magnetically operated and includes a float which moves in response to changes in the liquid level within the reservoir to magnetically open and close a fluid valve in response to that liquid level. Opening of the fluid valve may thereafter cause the opening of the second valve for other operations such as the drainage of the reservoir. In the second of the patents, there are also two valves, a pilot valve and a discharge valve. In this device, a float is held in a submerged condition for a time to create a superbuoyancy condition. When a sufficient superbuoyancy condition is achieved, the float suddenly rises to the surface of the liquid causing a snap action of the pilot valve. This opening of the pilot valve then quickly opens the discharge valve for the removal of material contained within the reservoir. In both of these patents, the pressure of the pneumatic system to which the trap is attached is the driving force that opens the discharge valve.
Since the operating valves and the drain valves are located within the reservoir, various disadvantages exist in the devices described in the above-identified patents. For example, the discharge valve or its operator may be damaged by, or may collect, dirt and other abrasive materials during the discharge operation. Also, they may be affected by corrosive action since they are in contact with the collected material. These deleterious conditions affect the future correct operation of the discharge valve. Further, since the discharge valve is located within the reservoir as part thereof, it is a difficult and an expensive procedure to replace components of this discharge valve. Since the pilot valve also is operated by the air pressure of the pneumatic system to which the reservoir is connected, this valve may become contaminated with some of the impurities.
Other drain valves open in response to a certain amount of fluids or other material being collected. One such drain valve system is disclosed in U.S. Pat. No. 4,779,640 issued to Ernie W. Cummings and Ralph W. Farkas. Another drain valve system is disclosed in U.S. Pat. No. 4,574,829 issued to Ernie W. Cummings and Nick Valk such patent being a continuation-in-part of U.S. Pat. No. 4,444,217, issued Apr. 24, 1984, there being a previously filed continuation-in-part application resulting in U.S. Pat. No. 4,562,855, issued Jan. 7, 1986.
Additional such drain valves are disclosed in U.S. Pat. No. 5,004,004 issued on Apr. 2, 1991, and U.S. Pat. No. 5,014,735 issued on May 14, 1991, both of which were issued to Ernie W. Cummings. The drain valve systems of U.S. Pat. Nos. 5,004,004 and 5,014,735 comprise a reservoir for receiving fluids and other material from a pneumatic system. The inlet is disposed in the base and fluids and other material flows into the reservoir via a port. The reservoir of the drain valve is selectively drained by a valve connected to an outlet port of the drain valve's reservoir. Thus, in order to drain fluids and other particulate material from the pneumatic system, the fluids and other particulate material must flow through the reservoir. However, inasmuch as the trigger point, i.e. the water level required for the float to pop up, is above the annular magnet, as will be appreciated by those skilled in the art, any particulate material that is magnetic, such as rust or other magnetic particulates, can potentially foul the annular magnet and impede the movement of the annular float. In order to open and close the drain valve of the system, a pneumatic valve operator is required, the valve operator being actuated by pressurized air selectively communicated to the valve operator by a magnetically controlled pilot valve. Still other of these known systems and devices for draining pneumatic systems are described in the background section of the above-identified patents and otherwise cited in such patents. Further, various drain valves marketed by Van Air Systems, Inc., Lake City, Pa., and Pa., and Hankison Corporation, Canonsburg, Pa., are illustrative of prior art devices.
Therefore, it is an object of the present invention to provide an automatic drain valve for discharging accumulations of fluids and foreign materials present in fluid handling systems.
Another object of the present invention is to provide a drain valve for fluid handling systems which does not require an external valve operator.
Still another object of the present invention is to provide a drain valve that discharges fluids and other materials without expelling air or other gases from the associated fluid handling system.
A further object of the present invention is to provide an automatic drain valve that is self-flushing so as to be essentially self cleaning.
Yet another object of the present invention is to provide an automatic drain valve which utilizes an internal pneumatic valve operator and an operatively associated linkage assembly for selectively opening and closing the drainage valve of the drain valve.
A further object of the present invention is to provide an automatic drain valve which utilizes a thru-port having direct fluid flow from inlet to outlet and that is in fluid communication with the reservoir such that fluid can flow into the reservoir and selectively activate the drain valve while particulate material is allowed to settle in the thru-port.
Still yet another object of the present invention is to provide an automatic drain valve which has a lower trigger point and in which the volume of fluid discharged is not limited by the volume of the reservoir.
Other objects and advantages over the prior art will become apparent to those skilled in the art upon reading the detailed description together with the drawings as described as follows.